William McGirr was the son of Arthur and Nancy McGirr. He joined Westland MM by request in 1809. In 1818, he married Rebecca Griffith, a widow. William and Rebecca joined the Hicksites in 1828.

McGirr was a leader of Pike Run Meeting, which was subordinate to Westland MM (H). McGirr was recognized as a minister. At some time around 1860, a member complained to McGirr about his ministry. He stopped attending meeting, and the meeting vacated his recording as a minister in response.

When Westland MM was attached to Salem MM (H) in Ohio, the memberships of William and Rebecca McGirr were transferred to Salem.